Mila Kunis Stalker – Wanted Poster Paints Scary Picture

11:25 AM PST -- TMZ has learned Mila's stalker has been taken into custody in Santa Monica, CA after police found him in an alley.

Be on the lookout for this man ... a convicted stalker who has terrorized Mila Kunis and is on the loose.

Stuart Lynn Dunn has been on the loose since escaping Saturday from a psychiatric facility near L.A. He's been twice convicted of stalking Kunis ... showing up at all hours at places she frequented.

Cops released these somewhat scary "Wanted" pics ... one of his mugshot and the other photo taken recently.

Cops say Dunn was last seen wearing a black zip-up jacket, light blue jeans and grey low-top converse.